LXR linux/drivers/rtc/rtc-mt7622.c

   1/*
   2 * Driver for MediaTek SoC based RTC
   3 *
   4 * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License as
   8 * published by the Free Software Foundation; either version 2 of
   9 * the License, or (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 * GNU General Public License for more details.
  15 */
  16
  17#include <linux/clk.h>
  18#include <linux/interrupt.h>
  19#include <linux/module.h>
  20#include <linux/of_address.h>
  21#include <linux/of_device.h>
  22#include <linux/platform_device.h>
  23#include <linux/rtc.h>
  24
  25#define MTK_RTC_DEV KBUILD_MODNAME
  26
  27#define MTK_RTC_PWRCHK1         0x4
  28#define RTC_PWRCHK1_MAGIC       0xc6
  29
  30#define MTK_RTC_PWRCHK2         0x8
  31#define RTC_PWRCHK2_MAGIC       0x9a
  32
  33#define MTK_RTC_KEY             0xc
  34#define RTC_KEY_MAGIC           0x59
  35
  36#define MTK_RTC_PROT1           0x10
  37#define RTC_PROT1_MAGIC         0xa3
  38
  39#define MTK_RTC_PROT2           0x14
  40#define RTC_PROT2_MAGIC         0x57
  41
  42#define MTK_RTC_PROT3           0x18
  43#define RTC_PROT3_MAGIC         0x67
  44
  45#define MTK_RTC_PROT4           0x1c
  46#define RTC_PROT4_MAGIC         0xd2
  47
  48#define MTK_RTC_CTL             0x20
  49#define RTC_RC_STOP             BIT(0)
  50
  51#define MTK_RTC_DEBNCE          0x2c
  52#define RTC_DEBNCE_MASK         GENMASK(2, 0)
  53
  54#define MTK_RTC_INT             0x30
  55#define RTC_INT_AL_STA          BIT(4)
  56
  57/*
  58 * Ranges from 0x40 to 0x78 provide RTC time setup for year, month,
  59 * day of month, day of week, hour, minute and second.
  60 */
  61#define MTK_RTC_TREG(_t, _f)    (0x40 + (0x4 * (_f)) + ((_t) * 0x20))
  62
  63#define MTK_RTC_AL_CTL          0x7c
  64#define RTC_AL_EN               BIT(0)
  65#define RTC_AL_ALL              GENMASK(7, 0)
  66
  67/*
  68 * The offset is used in the translation for the year between in struct
  69 * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA)
  70 */
  71#define MTK_RTC_TM_YR_OFFSET    100
  72
  73/*
  74 * The lowest value for the valid tm_year. RTC hardware would take incorrectly
  75 * tm_year 100 as not a leap year and thus it is also required being excluded
  76 * from the valid options.
  77 */
  78#define MTK_RTC_TM_YR_L         (MTK_RTC_TM_YR_OFFSET + 1)
  79
  80/*
  81 * The most year the RTC can hold is 99 and the next to 99 in year register
  82 * would be wraparound to 0, for MT7622.
  83 */
  84#define MTK_RTC_HW_YR_LIMIT     99
  85
  86/* The highest value for the valid tm_year */
  87#define MTK_RTC_TM_YR_H         (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT)
  88
  89/* Simple macro helps to check whether the hardware supports the tm_year */
  90#define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \
  91                                 (_y) <= MTK_RTC_TM_YR_H)
  92
  93/* Types of the function the RTC provides are time counter and alarm. */
  94enum {
  95        MTK_TC,
  96        MTK_AL,
  97};
  98
  99/* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */
 100enum {
 101        MTK_YEA,
 102        MTK_MON,
 103        MTK_DOM,
 104        MTK_DOW,
 105        MTK_HOU,
 106        MTK_MIN,
 107        MTK_SEC
 108};
 109
 110struct mtk_rtc {
 111        struct rtc_device *rtc;
 112        void __iomem *base;
 113        int irq;
 114        struct clk *clk;
 115};
 116
 117static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val)
 118{
 119        writel_relaxed(val, rtc->base + reg);
 120}
 121
 122static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg)
 123{
 124        return readl_relaxed(rtc->base + reg);
 125}
 126
 127static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set)
 128{
 129        u32 val;
 130
 131        val = mtk_r32(rtc, reg);
 132        val &= ~mask;
 133        val |= set;
 134        mtk_w32(rtc, reg, val);
 135}
 136
 137static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val)
 138{
 139        mtk_rmw(rtc, reg, 0, val);
 140}
 141
 142static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val)
 143{
 144        mtk_rmw(rtc, reg, val, 0);
 145}
 146
 147static void mtk_rtc_hw_init(struct mtk_rtc *hw)
 148{
 149        /* The setup of the init sequence is for allowing RTC got to work */
 150        mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC);
 151        mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC);
 152        mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC);
 153        mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC);
 154        mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC);
 155        mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC);
 156        mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC);
 157        mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0);
 158        mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
 159}
 160
 161static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
 162                                      int time_alarm)
 163{
 164        u32 year, mon, mday, wday, hour, min, sec;
 165
 166        /*
 167         * Read again until the field of the second is not changed which
 168         * ensures all fields in the consistent state. Note that MTK_SEC must
 169         * be read first. In this way, it guarantees the others remain not
 170         * changed when the results for two MTK_SEC consecutive reads are same.
 171         */
 172        do {
 173                sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));
 174                min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));
 175                hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));
 176                wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));
 177                mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));
 178                mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));
 179                year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));
 180        } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)));
 181
 182        tm->tm_sec  = sec;
 183        tm->tm_min  = min;
 184        tm->tm_hour = hour;
 185        tm->tm_wday = wday;
 186        tm->tm_mday = mday;
 187        tm->tm_mon  = mon - 1;
 188
 189        /* Rebase to the absolute year which userspace queries */
 190        tm->tm_year = year + MTK_RTC_TM_YR_OFFSET;
 191}
 192
 193static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
 194                                      int time_alarm)
 195{
 196        u32 year;
 197
 198        /* Rebase to the relative year which RTC hardware requires */
 199        year = tm->tm_year - MTK_RTC_TM_YR_OFFSET;
 200
 201        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year);
 202        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1);
 203        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday);
 204        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday);
 205        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour);
 206        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min);
 207        mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec);
 208}
 209
 210static irqreturn_t mtk_rtc_alarmirq(int irq, void *id)
 211{
 212        struct mtk_rtc *hw = (struct mtk_rtc *)id;
 213        u32 irq_sta;
 214
 215        irq_sta = mtk_r32(hw, MTK_RTC_INT);
 216        if (irq_sta & RTC_INT_AL_STA) {
 217                /* Stop alarm also implicitly disables the alarm interrupt */
 218                mtk_w32(hw, MTK_RTC_AL_CTL, 0);
 219                rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF);
 220
 221                /* Ack alarm interrupt status */
 222                mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA);
 223                return IRQ_HANDLED;
 224        }
 225
 226        return IRQ_NONE;
 227}
 228
 229static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm)
 230{
 231        struct mtk_rtc *hw = dev_get_drvdata(dev);
 232
 233        mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC);
 234
 235        return rtc_valid_tm(tm);
 236}
 237
 238static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm)
 239{
 240        struct mtk_rtc *hw = dev_get_drvdata(dev);
 241
 242        if (!MTK_RTC_TM_YR_VALID(tm->tm_year))
 243                return -EINVAL;
 244
 245        /* Stop time counter before setting a new one*/
 246        mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP);
 247
 248        mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC);
 249
 250        /* Restart the time counter */
 251        mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
 252
 253        return 0;
 254}
 255
 256static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 257{
 258        struct mtk_rtc *hw = dev_get_drvdata(dev);
 259        struct rtc_time *alrm_tm = &wkalrm->time;
 260
 261        mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL);
 262
 263        wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN);
 264        wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA);
 265
 266        return 0;
 267}
 268
 269static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 270{
 271        struct mtk_rtc *hw = dev_get_drvdata(dev);
 272        struct rtc_time *alrm_tm = &wkalrm->time;
 273
 274        if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year))
 275                return -EINVAL;
 276
 277        /*
 278         * Stop the alarm also implicitly including disables interrupt before
 279         * setting a new one.
 280         */
 281        mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN);
 282
 283        /*
 284         * Avoid contention between mtk_rtc_setalarm and IRQ handler so that
 285         * disabling the interrupt and awaiting for pending IRQ handler to
 286         * complete.
 287         */
 288        synchronize_irq(hw->irq);
 289
 290        mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL);
 291
 292        /* Restart the alarm with the new setup */
 293        mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL);
 294
 295        return 0;
 296}
 297
 298static const struct rtc_class_ops mtk_rtc_ops = {
 299        .read_time              = mtk_rtc_gettime,
 300        .set_time               = mtk_rtc_settime,
 301        .read_alarm             = mtk_rtc_getalarm,
 302        .set_alarm              = mtk_rtc_setalarm,
 303};
 304
 305static const struct of_device_id mtk_rtc_match[] = {
 306        { .compatible = "mediatek,mt7622-rtc" },
 307        { .compatible = "mediatek,soc-rtc" },
 308        {},
 309};
 310
 311static int mtk_rtc_probe(struct platform_device *pdev)
 312{
 313        struct mtk_rtc *hw;
 314        struct resource *res;
 315        int ret;
 316
 317        hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
 318        if (!hw)
 319                return -ENOMEM;
 320
 321        platform_set_drvdata(pdev, hw);
 322
 323        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 324        hw->base = devm_ioremap_resource(&pdev->dev, res);
 325        if (IS_ERR(hw->base))
 326                return PTR_ERR(hw->base);
 327
 328        hw->clk = devm_clk_get(&pdev->dev, "rtc");
 329        if (IS_ERR(hw->clk)) {
 330                dev_err(&pdev->dev, "No clock\n");
 331                return PTR_ERR(hw->clk);
 332        }
 333
 334        ret = clk_prepare_enable(hw->clk);
 335        if (ret)
 336                return ret;
 337
 338        hw->irq = platform_get_irq(pdev, 0);
 339        if (hw->irq < 0) {
 340                dev_err(&pdev->dev, "No IRQ resource\n");
 341                ret = hw->irq;
 342                goto err;
 343        }
 344
 345        ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq,
 346                               0, dev_name(&pdev->dev), hw);
 347        if (ret) {
 348                dev_err(&pdev->dev, "Can't request IRQ\n");
 349                goto err;
 350        }
 351
 352        mtk_rtc_hw_init(hw);
 353
 354        device_init_wakeup(&pdev->dev, true);
 355
 356        hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 357                                           &mtk_rtc_ops, THIS_MODULE);
 358        if (IS_ERR(hw->rtc)) {
 359                ret = PTR_ERR(hw->rtc);
 360                dev_err(&pdev->dev, "Unable to register device\n");
 361                goto err;
 362        }
 363
 364        return 0;
 365err:
 366        clk_disable_unprepare(hw->clk);
 367
 368        return ret;
 369}
 370
 371static int mtk_rtc_remove(struct platform_device *pdev)
 372{
 373        struct mtk_rtc *hw = platform_get_drvdata(pdev);
 374
 375        clk_disable_unprepare(hw->clk);
 376
 377        return 0;
 378}
 379
 380#ifdef CONFIG_PM_SLEEP
 381static int mtk_rtc_suspend(struct device *dev)
 382{
 383        struct mtk_rtc *hw = dev_get_drvdata(dev);
 384
 385        if (device_may_wakeup(dev))
 386                enable_irq_wake(hw->irq);
 387
 388        return 0;
 389}
 390
 391static int mtk_rtc_resume(struct device *dev)
 392{
 393        struct mtk_rtc *hw = dev_get_drvdata(dev);
 394
 395        if (device_may_wakeup(dev))
 396                disable_irq_wake(hw->irq);
 397
 398        return 0;
 399}
 400
 401static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume);
 402
 403#define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops)
 404#else   /* CONFIG_PM */
 405#define MTK_RTC_PM_OPS NULL
 406#endif  /* CONFIG_PM */
 407
 408static struct platform_driver mtk_rtc_driver = {
 409        .probe  = mtk_rtc_probe,
 410        .remove = mtk_rtc_remove,
 411        .driver = {
 412                .name = MTK_RTC_DEV,
 413                .of_match_table = mtk_rtc_match,
 414                .pm = MTK_RTC_PM_OPS,
 415        },
 416};
 417
 418module_platform_driver(mtk_rtc_driver);
 419
 420MODULE_DESCRIPTION("MediaTek SoC based RTC Driver");
 421MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
 422MODULE_LICENSE("GPL");
 423